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Stable N‐Heterocyclic Carbene (NHC)–Palladium(0) Complexes as Active Catalysts for Olefin Cyclopropanation Reactions with Ethyl Diazoacetate
Author(s) -
Martín Carmen,
Molina Francisco,
Alvarez Eleuterio,
Belderrain Tomás R.
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102900
Subject(s) - cyclopropanation , ethyl diazoacetate , carbene , olefin fiber , catalysis , chemistry , palladium , cyclopropane , ligand (biochemistry) , medicinal chemistry , styrene , organic chemistry , copolymer , ring (chemistry) , biochemistry , polymer , receptor
The Pd 0 complexes [(NHC)PdL n ] (NHC=N‐heterocyclic carbene ligand; L=styrene for n =2 or PR 3 for n =1) efficiently catalyse olefin cyclopropanation by using ethyl diazoacetate (EDA) as the carbene source with activities that improve on previously described catalytic systems based on this metal. Mechanistic studies have shown that all of these catalyst precursors deliver the same catalytic species in solution, that is, [(IPr)Pd(sty)], a 14e − unsaturated intermediate that further reacts with EDA to afford [(IPr)Pd(CHCO 2 Et)(sty)], from which the cyclopropane is formed.